The First Cadmium Enzyme – Carbonic Anhydrase 2 from the marine diatom Thalassiosira weissflogii

• Main Authors: Todd W. Lane, Mak A. Saito, Graham N. George, Ingrid J. Pickering, Roger C, François M. M. Morel, Woods Hole
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2005
• Subjects: Carbonic acid
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.693.2689; http://www-ssrl.slac.stanford.edu/research/highlights_archive/cd-ca.pdf

Cadmium is known to be extremely toxic to mammals, and is generally viewed alongside mercury an environmental problem and toxic element that is not used by nature in any way. We have reported the characterization of a previously unknown metalloenzyme from the marine diatom Thalassiosira weissflogii that specifically uses cadmium to achieve its biological function. This work shows that we need to revise our opinion of cadmium – it appears that it is not only used biologically, but may play a vital role in the global carbon cycle. Carbonic anhydrases catalyze the inter-conversion of carbonic acid and carbon dioxide: They are among the fastest enzymes known, with turnover numbers close to one million per second. Photosynthesis in green plants can use only molecular carbon dioxide, and not carbonic acid, and carbonic anhydrase thus represents the first step in the process of photosynthesis. In marine microalgae (e.g. diatoms), carbonic acid is taken